Rock bit



July 6, 1937. lM. H. ARNOLD ROCK BIT Filed Dec. 15, 1955 Patented July 6, 1937 UNITED STATES PATENT OFFICE 2,085,941 Roon Brr Matthew H. Arnold, Los Angeles, Calif.

Application December 13, 1935,'Serial No. 54,235 l 4 Claims. (Cl. 255-64) This invention relates to Ia drilling tool and relates more particularly to a rock drill for use in mining, quarrying and the like. A general object of this invention is to provide a practical,

5 effective rock drill embodying a detachable and replaceable bit or cutting head.

Another object of this invention is to provide a rock drill embodying a drill rod and a detachable cutting head connected and related so that the drilling blows and forcesare transmitted directly from the drill rod to the cutting head by large contacting surfaces lying in planes at substantially right angles to the longitudinal axis of the drill.

Another object of this invention is to provide a rock drill of the character mentioned in which rotation is directly transmitted from the drill rod to the cutting head by extensive cooperating surfaces of the rod and head. 20 Another object of this invention is to provide a rock drill in which the cutting head may be easily and Aquickly detached from the drill rod for replacement and resharpening.

Another object of this invention is to provide a rock drill that embodies a single simple securing member removably connecting the head with the drill rod, which member does not transmit the drilling forces between the rod and head and, therefore, is not distorted or made difficult of removal. y

Another object of this invention is to provide a rock drill that does not become caught or stuck in the drill bore by accumulations of. cuttings.

Another object of this inventionis to provide a rock drill that embodies novel means for discharging the circulation uid in a manner to prevent the accumulation of cuttings about the cutting head and drill rod.

A further object of this invention is to provide an improved rock drill of the character mentioned that is simple and inexpensive.

' The various objects and features of my invention will be fully understood from the following detailed description of .typical preferred forms and applications of the invention,' throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of one form of the drill provided by this invention showing the prin- 50 cipal parts in longitudinal cross section. Fig.V 2

is a bottom elevation of the drill being a view taken as indicated by line 2--2 on Fig. 1. Fig. 3 is a transverse detailed sectional view taken as indicated by line 3--3 on Fig. l. Fig. 4 is a side elevation of the cutting head apart from the includes, generally, a drill rod I0, a bit or cutting head II and means I2 for removably securing the head II to the rod II).

The drill rod I is provided to carry the cutting head II andA to transmit the impact or drilling forces to the head. The rod I 0 is an elongateV member and its length may depend upon the character ofthe work or drilling operations. In accordance with the invention the end portion of the rod I0 which carries the head II is oval or polygonal in transverse cross section. `lli desired, the rod Ill may be of such configuration throughout its length. In the particular form of the invention illustrated in the drawing the rod I0 is hexagonal in transverse cross section. In accordance with the invention the end I3 of the drill rod I0 is at .and at right angles to the longitudinal axis of the rod. A central longitudinal fluid passage I4 is provided in the drill rod I0 and extends through the rod from one end to the other.

The bit or cutting head II is the active or cutting element of the drill and is detachably secured to the rod I0 by the means I2. The cutting head II is a simple, integral member whose innerer upper portion may be substantially cylindrical as illustrated in the drawing, The outer or lower portion of the head II has a ilaring or convergent exterior I5 so that the active end of the Vhead is larger in diameter than the drill rod I0. The active face' or cuttingface of the head I I preferably lies in a plane substantially'normal to the longitudinal axis of th'e drill and is provided with suitable cutting parts or teeth I6. In the particular case illustrated in the drawing the teeth I6 are straight and are substantially radial. It is to be understood that the cutting head II may be provided with teeth or cutting parts of any suitable character or conguration. It is preferred to hard face the teeth I6 and the lower end of the head I I or to provide the cutting faces of the head .with hard .wear resisting material. In accordance with the invention a socket Il is provided in the head II to receive the end portion of the drill rod I0. 'Ihe socket l'I is of substantial depth and is shaped to accurately or properly receive the polygonal rod I'Il. Where the rod I0 is hexagonal as illustrated the socket I1 is of corresponding configuration. The bottom wall I8 of the socket Il is flat and normal to the longitudinal axis of the drill to cooperate with the end I3 of the drill rod I8. It will be apparent how the end I3 of the drill rod I0 cooperating with the bottom wall I8 of the socket I1 directly transmits the drilling forces from the rod IIJ to 5 the cutting head II. In a similar manner the sides ofthe polygonal drill rod I 6 cooperate with the iiat walls of the polygonal socket I1 l'orthe transmission or rotation from the rod to the head II. 'y 10 'I'he means I2 for removably securing the cutting head II to the drill rod I Il dependably and rigidly secures the head to the rod and yet permits the easy rapid removal of the head I I after operation of the drill. Ihe securing or connecting means I2 includes or provides a socket 20 in the end portion of the drill rod I0 and an opening 2l in the head II. "The socket20 and the opening 2,.I are preferably co-axial with the central longitudinal axis of the drill and are, therefore, in axial alignment. 'Ihe means I2 comprises a single bolt or connecting member 22 extending through the opening 2I and threaded into the socket 20. The threads of the socket 20 and the connecting member 22 are preferably left-hand 25 threads. A head 23 is provided on the outer end of the connecting member 22 and is received in a socket or counter-bore 24 at the outer end of the opening 2|. The inner face of the head 23 and the inner wall of the counter-bore 24 may be tapered as illustrated. A polygonal wrench socket 25 is provided in the head 23 to facilitate the threading of the connecting member 22. The head 23 of the connecting member 22 is recessed or countersunk in the counterbore 24 beyond the active parts or teeth I6 of the cutting head II and may be provided with an annular cutting edge 23*l for engaging the central part of the rock or work. Threading or tightening of the connecting member 22 in the socket 20 securely attaches 40 the cutting head II to the drill rod I0 to hold the bottom wall I8 of the socket I1 in cooperation with the end I3 of the drill rod III.

The inventionprovides novel and particularly eiective means for discharging the circulation medium or iiuid to ilush the cutting teeth I6 and to carry the cuttings away from the head II and the rod I Il. In accordance with the invention the bolt. or connecting member 22 is tubular, having a central longitudinal opening 26. The upper end of the opening 26 directly communicates with vthe fluid passage I4 and the loweiend of 'the opening 26 discharges downwardly through the wrench socket 25. A groove 21 surrounds the connecting member 22 at the contacting rod end I3 and socket bottom I8. In practice the groove 21 may be formed in both the bottom of the socket I1 and the end of the drill rodA III. One or more lateral ports 28 are provided in the connecting member 22 to place the groove 21 in communication with 80 the fluid opening 26. Substantially radial uid channels 29 extend outwardly from the annular groove 21. In the particular structure illustrated in the drawing there are, two iiuid channels 29 provided in the bottom wall I8 of the socket I1. Discharge channels 30 extend from the outer ends of the radial channels 29 to discharge the :duid at the upper or inner end of the cutting head 1I I. Where the radial'channels 29 are provided in the head II it is preferred to also provide the discharge channels 30 in the head, it being understood that the channels 29 and 38 may be formed in the drill rod I0, if desired. 'Ihe ports 28, the

groove 21 and the channels 29 conduct iiuid from the opening 26 to the channels 38 and the channels 30 discharge this fluid axially-along the drill rod II! at the outer end of the head II to carry the cuttings away from the cutting head II and the end portion of the rod so that the cuttings do not accumulate about thehead and rod.

In the operation of the drill provided by this 5 invention the drilling forces are transmitted directly from the drill rod I0 to the head I I through the contacting surfaces I3 and I8 while the drilling or turning forces are directly transmitted from the rod I0 to the head II through the con- 10 tacting side surfaces of the rod I0 and the side walls of the socket I'I. v'Ihus the connecting member 22 does not transmit any of these forces and, therefore, is not subject to wear or distortion. The connecting member 22 dependably'connects 15 the head II to the rod I0 without becoming loosened. The iluid discharged from the opening 26 fully ushes the teeth I6 and carries the cuttings away from the active end of the head II while the fluid discharged from the channels 30 carries 20 the cuttings away from the head and the inner end of the rod EIU to prevent the cuttings from accumulating about the head. Accordingly, there I is little or no tendency for the .drill to become stuck or caught in the drill bore. When the cut- 25 ting teeth I6 become dulled or when it becomes desirable to replace orrecondition the cutting head II, the head may be easily removed from the drill rod I0. To remove the cutting head II from the rod II) the connecting member 22 is un- 30 threaded from the socket 20 and is removed from the socket and the opening 2I. Due to the fact that `the connecting member 22 is not subjected to the action of the drilling forces it is easily removed following the use or operation of the drill. 35 Following the removal ofthe connecting member -22 the cutting head I-I may be easily slipped or removed from the drill rod I8. A new or replacement cutting head-may then be arranged on the rod I8 and secured to the rod by the connecting 40 member 22 or bya new or replacement connecting member 22. The drill is then reconditioned for further use. 'I'he cutting head vII and the connecting member 22 are easy and simple to manufacture so that the drill is inexpensive.- 45

Fig. 5 of the drawing illustrates another form of the invention embodying a modied or alternative means I2* for removably securing the head I I to the drill rod III. The head or bit II and the rod I0 may be substantially the same as de- 50 scribed above. The securing or connecting means I2 includes a bolt or connecting member 22* passed through the central opening 2I in the bit II and threaded into the opening 20 in the rod I0. The member 22i has a polygonal 55 head2# received in the counter-bore 24 of the bit II. The head 23L is such that it may be readily engaged by a wrench when seated in the counter-bore 24. In accordance with the form of the invention illustrated in Fig. 5 the head 23a of 60 the connecting member 22a is pointed or provided with a cutting part 40. The cutting part 40 may be pyramidal or conical as illustrated and is adapted to act on the rock or work. The provision of the cutting part 40 adapts the bit for 65 use in drilling asphalt or the like. When the connecting member 22e is threaded in the opening 28 to have its head 23u clamp against the bottom wall of the counter-bore 24 it securely and' dependably attaches the bit II to the rod I0. A 70 central longitudinal passage or opening 26L enters theconnecting member 22* from its upper end and terminates at a point spaced from the head 23". Lateral ports '28* are provided in the connecting member. 22"b to communicate with the 75 inner portion of the opening 26. The ports 28* place the opening 26e in communication with the annular groove 21 whereby the circulation fluid may flow from the ports 2lia through the groove 21, the channels 29 and the discharge channels 30. The operation of the form of bit illustrated in Fig. of the drawing is substantially the same as that of the previously described form of the invention, except that the cutting part 40 acts on theY central portion of the bore hole and the circulation fluid is only discharged outwardly or rearwardly from the channels 30.

Having described only typical preferred forms and applications of -my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those-skilled in the art or fall within the scope of the following claims:

Having described my invention, I claim:

1. A' rock drill comprising, a drill rod, a cutting. head having a socket receiving an end portion of the rod to have the end of the rod bearon its bottom wall, there being avfluid passage extending longitudinally through the rod and head to discharge from the active end of the head and a channel between the contacting surfaces of the rod and head communicating with the passage and discharging at the other end of the head, and means removably'securing the head to the rod.

2. A rock drill comprising a rod having a fluid passage, a cutting head, the rod and head having telescopically related force transmitting parts,

there being channels between the contacting. surfaces of said parts communicating with the passage and discharging into the drill bore at the outer end of the-head, and a member removably connecting the head to the rod and having an opening communicating with the passage and discharging at the active end of the head.

3. A rock drill comprising a rod having a uid passage, a cutting head, the rod and head having telescopically related force vtransmitting parts, there being channels between 'the contacting surfaces of said partsand adapted to discharge into the drill bore, and a. member threaded into the passage to removably secure the head to the rod and having an opening communicating with the passage and discharging into the bore and having a port carrying fluid .from said opening to the channels.

4. A rock drill comprising a polygonal rod having a longitudinal fluid passage, a cutting head having a polygonal socket receiving an end part of the rod and having an opening aligned with the passage, there being a channel between contacting surfaces of the rod and head discharging at the outer end of the head, and a connecting member passed through the opening, threaded into the passage and engaging against the head to removably secure the head to the rod,

there being a longitudinal opening in the member receiving iluid from the passage and discharging at the active end of the head and a port in the member placing the channel in communication with the last named opening.

MATTHEW H. ARNOLD. 

